A large percentage of people on the internet are atheist. So naturally a decent amount of people assume other people who haven't stated otherwise or given indication otherwise share similar beliefs, especially if they exemplify values we agree with.
Bill Gates and Morgan Freeman are self-declared agnostics. Neil Degrasse Tyson doesn't declare himself anything, he doesn't give a **** either way. And it all has to do with your concept of judgement as well. I had a religion teacher who was very active in his church, and he told me he doesn't believe in eternal punishment, that a loving God wouldn't do that to his people, he thinks they might be punished for a time, and then sent up to Heaven. There's not a hard and fast determination of Heaven and Hell.